Microstructure, Morphology and Properties of Titanium Containing Graphite-Like Carbon Films Deposited by Unbalanced Magnetron Sputtering

A series of graphite-like carbon films with a titanium concentration of about 3.0 at.% were successfully deposited on silicon wafer substrates using an unbalanced magnetron sputtering system with different bias voltages. The microstructure, surface morphology, and properties of the titanium-containing graphite-like carbon films were subsequently studied using different characterization techniques. The results show that the resulting titanium-containing graphite-like carbon films are completely dominated by sp² sites and that these films have moderate hardness, low internal stress, and superior tribological properties with low friction and a high load-bearing capacity. The hardness (H), elastic modulus (E), H/E, H ³/E ², and internal stress of the titanium-containing graphite-like carbon films initially increase with increasing bias voltage, only to be followed by a decrease with further increases in the bias voltage. Tribologically, the studied carbon film shows a slight increase in friction with increasing bias voltage, while the wear rate initially decreases, followed by an obvious increase. The tribological properties of the studied titanium-containing graphite-like carbon films are greatly improved under the liquid paraffin-lubricated condition, achieving extremely low friction (~0.045) and wear (~10⁻⁹ mm³/Nm). The effect of bias voltage on the microstructure and properties of the titanium-containing graphite-like carbon films is discussed in detail.